Diffraction Gratings
According to one aspect of the art, diffraction gratings are known which may consist of periodic structures which cause incident light to diffract. In such cases, diffraction may occur both in transmissive (e.g. prisms) or reflective (e.g. CDs and DVDs) modes, and such diffraction may be due to the transparency or reflective nature of the substrate which contains the periodic structure. In such case, the pitch or spacing of the periodic structures, which is typically known as the period of the grating, has an inverse effect on the dispersion angle.
In one such aspect according to the art, an array of nanoholes with periodicity in the visible spectrum (λ) and hole diameters smaller than λ/2 may also diffract light to create structural colors. In one such aspect, the physical configuration of the nano-features may define the intensity of the diffracted wavelengths which may be substantially higher than which may be obtained using more conventionally available micro-scale gratings. For any diffraction grating, the intensity of the maxima peaks, in transmission or reflection, increases as a function of the number of slits (N) over a given area, specifically increasing as N2. The colors seen in the first order maxima peaks become more distinguishable leading too higher chromatic resolution—i.e. crisper and clearer defined colors. For example, a diffraction grating with a spacing of 500 nm will exhibit intensity four times that of a grating spaced at 1000 nm, while producing clearly defined color bars. Visually the nanoscale features appear brighter, especially noticeable in dimmer light, and their specific colors appear more solid as the viewing angle changes (i.e. less “rainbowing” of colors). Diffraction gratings split white light into multiple colors. The intensity (I) and chromatic resolution of the colors depend on the size and density of slits in a given area, in accordance with the relation:
  I  ∝            [                        ∑                      p            =            1                                N            /            2                          ⁢                                  ⁢                  cos          ⁡                      (                                          (                                                      2                    ⁢                                                                                  ⁢                    p                                    -                  1                                )                            ⁢              π              ⁢                              d                λ                            ⁢              sin              ⁢                                                          ⁢              θ                        )                              ]        2  
Due to their unique brilliant optical effects, these nano-scale gratings have been implemented in some applications to replace holograms such as for some security applications in some aspects known in the art.
Motion and Animation Displays
According to another aspect of the art, motion and animation optical displays are known which provide the appearance or illusion of motion using multiple frames of a similar or related image shown in different positions, and exposing one frame at a time to a viewer. In one such aspect, a shutter or grating layer may be moved over a second layer showing multiple overlapping frames interlayered with each other to show successive frames to a viewer, such as in a “scanimation” type shutter animation display. According to a further aspect of the art, one or more of diffraction grating secondary layers, polarization secondary layers, lenticular lenses, holographic interference patterns and/or light wave interference may be used to alternate or selectively view individual image frames in other motion or animation displays.